In recent years, flat TV receivers capable of displaying 3D video to viewers (what is called 3D-compatible) have been being developed enthusiastically. Also in the TV industry, the necessity of generating 3D video data that are in such a form as to enable display of 3D video to viewers has increased. It is expected that the demand for 3D-shooting-compatible TV camera systems capable of producing 3D video data will increase.
Three-dimensional video data can be produced by simultaneously producing two video data having a parallax. In general, 3D shooting systems in which two imaging units are spaced from each other in the left-right direction are used for this purpose (refer to Patent documents 1-3).
In such 3D shooting systems, the distance between the optical axes of optical systems included in the two respective imaging units is called a baseline length and the parallax between two video data obtained by the two imaging units can be adjusted by changing the baseline length.
For example, Patent document 1 discloses a technique that in a single camera having two imaging units an optimum baseline length is calculated according to a zoom lens position and a focus lens position and the distance between the imaging units is controlled so as to become equal to this baseline length.
Patent document 2 discloses a technique that in a camera which performs 3D shooting using two optical systems and a single imaging device an optimum baseline length between the two optical systems is calculated from a focal length and a subject distance and the distance between the two optical systems is controlled so as to become equal to this baseline length.
Patent document 3 discloses the following technique in a system having two cameras. When a user sets a desired subject distance, a vergence angle and a baseline length between the two cameras are calculated on the basis of the subject distance and displayed on a display unit and the vergence angle and the baseline length between the two cameras are changed.